The proposed five-year career award will provide Kimberly Brouwer, Ph.D., with protected time and the methodological expertise in geographic information systems (GIS) and social epidemiology needed to conduct innovative research on risk environments related to drug use and bloodborne infections. Dr. Brouwer previously received a Fulbright award for infectious disease epidemiology research, and has 9 papers published or in press. She recently left the Centers for Disease Control and Prevention for academia and is now a post-graduate researcher at the University of California, San Diego. It is critical at this stage in her career that she be afforded the time and training opportunities needed to become established as an independent public health investigator. The career and training goals of this proposal are to: 1) Develop skills for building a complex model within a GIS environment, 2) Gain proficiency in spatial and multi-level analysis, 3) Increase understanding of the intersection of environmental and social factors in relation to drug use and consequent diseases, 4) Obtain ongoing training in the ethical conduct of research, and 5) Build general skills for an academic career. The plan includes structured coursework and mentoring by a group of experts in drug abuse, GIS, and social epidemiology. A key component of training will involve designing and conducting a study to characterize the risk environment associated with injection drug use in Tijuana, Mexico. While much research has been done to characterize individual-level risk factors for drug use, comparatively little is known about contextual determinants. The aims of the proposed research are to: 1) Develop a GIS model of social and environmental factors potentially affecting injection drug users (IDU) in Tijuana, 2) Determine the extent to which social and environmental factors relate to use of specific injection drug combinations, risk behaviors for bloodborne infections, and barriers to accessing drug abuse treatment and sterile syringes, 3) Assess how the spatial distribution of those recruited through respondent-driven sampling relates to IDU risk behaviors and disease prevalence. Injection drug use, particularly along the U.S.-Mexican border, is considered to be a major contributor to a recent rise in HIV and Hepatitis C infections. This project will take place along one of the busiest crossings of the U.S.-Mexico border. Gaining a better understanding of environmental factors that affect disease transmission in IDUs in this area can be used to better design health interventions on both sides of the border. Data generated from this study will be used by the applicant to develop a subsequent R01 application.